# Abbe Number Calculator

Posted by Dinesh onUse this simple **abbe number** (**V-number** or **constringence**) calculator to measure of the material's dispersion, with high values of V indicating low dispersion in optics and lens design.

? in nm | Fraunhofer's symbol | Light source | Color |
---|---|---|---|

365.01 | i | Hg | UV |

404.66 | h | Hg | violet |

435.84 | g | Hg | blue |

479.99 | F' | Cd | blue |

486.13 | F | H | blue |

546.07 | e | Hg | green |

587.56 | d | He | yellow |

589.3 | D | Na | yellow |

643.85 | C' | Cd | red |

656.27 | C | H | red |

706.52 | r | He | red |

768.2 | A' | K | IR |

852.11 | s | Cs | IR |

1013.98 | t | Hg | IR |

## Abbe Number (V-number) Calculation

### Formula:

V_{D} = (n_{D} - 1) / (n_{F} - n_{C})

where,

n_{D}, n_{F} and n_{C} - the refractive indices of the material at the wavelengths of the Fraunhofer spectral lines of D-, F- and C respectively.

V_{D} - abbe number of material